When planning their gardens, many gardeners recognize the relationships between their plants and local wildlife. This ecological perspective has gardening implications for each of several categories of wildlife: birds, mammals, reptiles, and various invertebrates.
An overarching concept for this ecological perspective is the food chain. Insects are low on the food chain, so selecting plants according to the needs and preferences of insects has impacts on the higher levels of the chain. As a basic example, plants that attract insects to the garden increase the food source for birds and reptiles, and an increase in the numbers of birds and reptiles provides food for carnivores.
Gardeners often want to grow flowering plants that attract bees, butterflies, and other pollinators. Those gardeners might intend primarily to support plant pollination and garden aesthetics (butterflies always delight the eye), but their plant selection also supports the food chain.
As we develop our garden and select plants from this ecological perspective, we might favor plants that are native to our local environment. The rationale for preferring native plants reflects an assumption that the insects and other wildlife in our gardens know and prefer plants that they have encountered throughout their lives, and the lives of their preceding generations. Surely, wild creatures communicate survival knowledge to their offspring at least by demonstration.
For such reasons, I have favored native plants because of their presumed appeal to local wildlife, in addition to the compatibility of native plants with native soil, climate, and plant communities. The logical application to this view is for the gardener to fill the garden with native plants.
This approach to landscaping succeeds. We are not here to negate gardening in the Monterey Bay area with California native plants.
I have become aware, however, of another layer of thought to consider.
In a recent issue of Horticulture magazine, entomologist Eric Grissell described a wildlife gardening study, “Plants for Bugs,” conducted by England’s Royal Horticultural Society.
I visited the project’s website to learn about this project. Its first bulletin for gardeners is titled “Gardens as Habitats for Pollinators” (August 2015). This column addresses the study’s methods and findings related to pollinators.
The study’s approach was to observe the numbers of times pollinating insects land on flowers of plants with each of three different origins: United Kingdom natives; other Northern hemisphere natives, i.e., plants from regions similar to the UK; and Southern hemisphere natives, i.e., plants from climates and habitats that are different from the UK.
The study’s original recommendations are oriented to the United Kingdom, but they could be applied reasonably to other gardening environs. Accordingly, I have modified the wording of these statements to relate them to gardening in the Monterey Bay area.
- Gardeners should plant a mix of flowering plants from different countries and regions;
- Plant selection should emphasize plants that are native to California’s central coast, or to the Mediterranean climate areas;
- Regardless of plant origins, the more flowers the garden can offer throughout the year, the greater number of pollinators it will attract and support.
Plants that are native to the garden area are still important, but gardens serve pollinators best when they have large numbers of flowers and a long flowering season, regardless of the origins of the plants.
In a future column, we’ll review this project’s second bulletin, “Gardens as Habitats for Plant-Dwelling Invertebrates” (August 2017).